Team:Bielefeld-CeBiTec/Project/translational system
Translational System Overview
The genetic information, coded in the DNA, are the basis for the expression of proteins and therefore are essential for all living organisms.
The expansion of the genetic code, by adding new bases to the DNA, offers multiple possibilities, like the coding of non-canonical amino acids. At the same time, it is going to create new challenges.
Beside a preservation system for the unnatural-base pairs (UBP) , the whole transcriptional and translational system has to be adapted if a non-canonical amino acid (ncAA) is coded by UBPs.
The incorporation of ncAA generates many new properties of proteins and therefore a wide specter of applications. It can be achieved either by the use of UBPs or coded by an amber-stop codon.
The incorporation of a ncAA by an amber-stop codon requires the recognition of the codon and a tRNA/aminoacyl-synthetase (tRNA/aaRS) pair which is able to accept and bind the ncAA (to charge the tRNA with the ncAA).
In addition, the tRNA/aaRS pair should be very specific in the incorporation of the ncAA. Therefore a library of the mutated orthogonal tRNA/aaRS is generated and undergoes numerous rounds of positive and negative selection for the adaption of the codon recognition and the amino acid binding. The selection results in a synthetase which can be expressed efficiently in E. coli and is able to reliable incorporate an unnatural amino acid.
